Sensorless SVM direct torque controlled interior permanent magnet synchronous drive

This paper presents a sensorless SVM direct torque control (DTC) scheme for interior permanent magnet (IPM) synchronous motors. A speed observer based on the stator flux linkage is investigated in this paper. In addition, an initial rotor position estimator is also introduced. By using high frequency signal injection and exploiting the saliency property of an IPM motor, the initial rotor position can be found. Both the position and speed estimators are simple, software-based and irrespective to machine parameters. Hence, the basic advantages of a DTC controller are retained. The sensorless DTC scheme is simulated in MATLAB and tested experimentally.